In Crookedstar's Promise, Rainflower is Crookedkit's mother, and she was so pride of his bravery and determination (also how handsome he was) but all that changed when he slammed he jaw into a rock at Sunningrocks. His name was changed from Stormkit to Crookedkit, since his jaw would never heal. Rainflower doesn't hate him, but seems to show it like that when she refuses to look at him, probably because she is sad about his new imperfection when he was once so handsome.
I personally don't think Rainflower hates Crookedstar because they are mother-son. But it's probably just a rumor.
Oakheart's parents are Shellheart and Rainflower. Shellheart was a RiverClan warrior and Rainflower was a former RiverClan queen.
Crookedstar's and Oakheart's mother is Lilystem. But in Crookedstar's Promise, in the alligiences it says Rainflower.
Moonstone
It is a rabbit being hunted by WindClan warriors. The rabbit is killed by a monster on the Thunderpath. Crookedkit is not seen. This answer is from the book "Crookedstar's Promise."
His wife pushed him into the wall.
kittypet
Brightsky and Mudclaw. It says so in Crookedstar's promise.
The rhino was the animal that charged at Crooked Kit in warriors. It was however killed by the warriors who were highly skilled in hunting.
No
Nobody really hated him, but there were many people who hated his views.
The Hated ended in 1990.